The present invention relates to an endoscope comprising a distally disposed lens and an image transmission system which transmits the image from the lens to the proximal end.
Endoscopes of this kind are commonly known and are used, for instance, in medicine or engineering applications for observing cavities, particularly under aggravated conditions.
The image transmission system may consist of one or several distally disposed semiconductor chips such as CCD elements, a relay lens system preferably including rod lenses or a fibre bundle.
In operation and/or during cleaning or sterilisation the endoscopes are frequently exposed to elevated temperaturesxe2x80x94up to 140xc2x0 C. when they are sterilised by autoclavexe2x80x94pressures and/or aggressive mediaxe2x80x94e.g. when they are sterilised in solutions. Depending on their design the endoscopes are specified only up to defined ambient conditions. When these limits are exceeded the most different types of damage may occur:
As a result of improper handling temperatures and/or pressures may occur which are above the admissible limits. As a consequence, joints such as the connection between the distal terminal window of the lens and the outside tube may be damaged so that the endoscope is no longer fluid tight and humidity can penetrate into the interior. In endoscopes with a semiconductor chip this chip may be destroyed by excessively high temperatures. Similar conditions prevail when the endoscope is exposed to other ambient conditions for which it is not specified, and/or to the action of aggressive media.
Moreover, specifically the elongate introducing elements of the endoscopes may be exposed to shocks or impacts when they are not carefully handled. This may easily result in damage, e.g. on rod lenses, particularly in breaking. Even if no lenses are broken, the endoscope might be misadjusted.
The operator frequently does not even note that the endoscope is employed beyond the specified conditions. This leads not only in unjustified complaints versus the endoscope manufacturer but results also in sudden failure of the endoscope during application or causes other damage induced by the endoscope.
The present invention is based on the problem of improving an endoscope of the claimed general type in a way that particularly operating conditions beyond the specified range can be recognised.
In accordance with the invention the endoscope comprises at least one sensing and recording device disposed in the interior of the endoscope, which detects the particular temperatures, pressure, humidity, irradiation, ambient conditions and/or shock or impact loads which the endoscope is exposed to.
The sensing and recording device which is provided in accordance with the invention and integrated into the endoscope permits the detection of the history of this endoscope so that the causes of failure etc. can be reconstructed.
Moreover, the information recorded or stored by the sensing and recording device, which refers to the history can be extracted from the outside without disassembly of the endoscope. An operator can hence recognize at any time whether the endoscope has been exposed to unacceptable ambient conditions in the past. This enables the operator in particular to screen an endoscope involving a high probability of failure on account of its history before failure of the endoscope occursxe2x80x94e.g. during a surgical operation.
The sensing and recording device provided and configured in accordance with the invention has hence a checking function which allows for endoscope monitoring.
The extraction from the outside may take place either by the fact that the sensing and recording device is visible through a window in the endoscope or that the stored information is transmitted to the outside e.g. electrically and particularly without contact.
The sensing and recording device is preferably so configured that it detects and stores the maximum value occurring in each case or, in an alternative or additionally, counts or stores the number of critical situations or states.
The term critical situations or states is to be understood here to denote conditions in which the permissible maximum values are exceeded for the individual parameters such as temperature, pressure, etc.
On principle any means whatsoever may be used as sensing and recording device, which comprise, for instance, mechanical indicators and/or electronic sensors, on the condition that these means are only able to detect the occurring values of the respective ambient condition and to store at least the peak value.
A particularly simple configuration of the sensing and recording device for detection of the occurring temperature or humidity comprises a color indicator element which signals the temperature or humidity value by its color. The change of color is preferably irreversible so that the maximum temperature, for instance, to which the endoscope had been exposed, can be reliably established even subsequently.
The sensing and recording device comprises a membrane which closes a small space isolated from the interior proper of the endoscope, where air is contained under normal pressure, and which breaks at a specified pressure difference between the environment and the small space.
The sensing and recording device for the detection of shock or impact loads also comprises a break-off element, which breaks at a specified load.
It is preferablexe2x80x94as has been set out in the foregoingxe2x80x94to provide for external extraction of the information recorded or stored by the sensing and recording device without disassembly of the endoscope it is preferred that at least one of the indicators of the sensing and recording device is visible from the outside. To this end, the indicator or indicators of the sensing and recording device in the endoscope may be disposed behind a window so that they are visible from the outside. This window is preferably the lens window of the endoscope so that it is not necessary to leave an additional window open in the outside wall of the endoscope.
As has been set out in the foregoing, it is possible to use also electronic sensors in addition to the aforementioned mechanical sensors or indicators operative by change of colour.
It is, of course, also possible that the sensing and recording device comprises at least one sensorxe2x80x94instead of or additionally to the aforementioned indicator elements indicating by change of color or mechanically that a limit has been exceededxe2x80x94for electronically detecting the specific temperature, pressure, humidity, irradiation, other ambient conditions or shock or impact loads which the respective endoscope had been exposed to. To this end the endoscope comprises an energy accumulator, a sensor detecting one of these parameters and converting it into an electrical signal, as well as a signal processing unit which is capable of performing a preliminary processing of the parameters and storing in particular the deviation beyond parameters. Moreover, a transmitter unit is provided for transmitting the stored information to the outside.
It is furthermore preferred that the sensing and recording device additionally includes a timer system so that the time of occurrence of a critical state will be detected and output in combination with the detected parameters. With these provisions it is possible, for instance, to associate improper handling of an endoscope with an identified user.
This transmitter unit may be a plug, however a wireless system is preferred which may be configured in particular in the manner of a telemetric system.
It is moreover preferred, that the energy accumulator can also be charged from the outsidexe2x80x94via plug or, equally preferably, without contactxe2x80x94because in such a case it is not necessary to open the endoscope for maintenance of the sensing and recording device.
When the sensing and recording device is configured as electronically operating sensing and recording device, as has been set out in the foregoing, it is furthermore preferred that, the sensing and recording device performs recognition of further events only upon the lapse of a certain predetermined interval when certain temperature and pressure thresholds are exceeded. With this provision it is possible in particular that the sensing and recording device detects the number of sterilization cycles which are then weighted in correspondence with their respective duration.
It is moreover expedient that the receiver means be so configured that it receives the signals from a plurality of sensing and recording device. To this end each sensing and recording device transmits an unambiguous identification of the respective end, and particularly the deviation beyond set parameters, separately for each endoscope.
In the improvement of the invention according to claim 19 the sensing and recording device detects or records additionally also the functional parameters of the endoscope, such as the position of a zoom or variable lens, the position of an endoscope-internal sensing and recording system, etc.